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Far-red light-regulated efficient energy transfer from phycobilisomes to photosystem I in the red microalga Galdieria sulphuraria and photosystems-related heterogeneity of phycobilisome population.(Report)

BBA - Bioenergetics, Feb, 2011, Vol.1807(2), p.227(9) [Periódico revisado por pares]

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  • Título:
    Far-red light-regulated efficient energy transfer from phycobilisomes to photosystem I in the red microalga Galdieria sulphuraria and photosystems-related heterogeneity of phycobilisome population.(Report)
  • Assuntos: Public Television -- Physiological Aspects ; Fluorescence -- Physiological Aspects ; Photosynthesis -- Physiological Aspects ; Sulfur -- Physiological Aspects
  • É parte de: BBA - Bioenergetics, Feb, 2011, Vol.1807(2), p.227(9)
  • Descrição: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.bbabio.2010.10.018 Byline: Igor N. Stadnichuk, Alexander A. Bulychev, Evgeni P. Lukashev, Mariya P. Sinetova, Mikhail S. Khristin, Matthew P. Johnson, Alexander V. Ruban Keywords: Galdieria; Fluorescence; Photosystem I (II); Phycobilisome(s) Abbreviations: ApcD, one of the two terminal phycobilisome emitters; DCMU, 3-(3,4-dichlorphenyl)-1,1-dimethylurea; L.sub.CM, phycobilisome core-membrane linker protein and terminal emitter; PBS, phycobilisome(s); P700, primary electron donor of the PSI reaction center; P700.sup.+, cation radical of P700; PSI (PSII), photosystem I (photosystem II) Abstract: Phycobilisomes (PBS) are the major photosynthetic antenna complexes in cyanobacteria and red algae. In the red microalga Galdieria sulphuraria, action spectra measured separately for photosynthetic activities of photosystem I (PSI) and photosystem II (PSII) demonstrate that PBS fraction attributed to PSI is more sensitive to stress conditions and upon nitrogen starvation disappears from the cell earlier than the fraction of PBS coupled to PSII. Preillumination of the cells by actinic far-red light primarily absorbed by PSI caused an increase in the amplitude of the PBS low-temperature fluorescence emission that was accompanied by the decrease in PBS region of the PSI 77 K fluorescence excitation spectrum. Under the same conditions, fluorescence excitation spectrum of PSII remained unchanged. The amplitude of P700 photooxidation in PBS-absorbed light at physiological temperature was found to match the fluorescence changes observed at 77 K. The far-red light adaptations were reversible within 2-5min. It is suggested that the short-term fluorescence alterations observed in far-red light are triggered by the redox state of P700 and correspond to the temporal detachment of the PBS antenna from the core complexes of PSI. Furthermore, the absence of any change in the 77 K fluorescence excitation cross-section of PSII suggests that light energy transfer from PBS to PSI in G. sulphuraria is direct and does not occur through PSII. Finally, a novel photoprotective role of PBS in red algae is discussed. Article History: Received 12 August 2010; Revised 15 October 2010; Accepted 24 October 2010
  • Idioma: English

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